Spark plug



Feb. 15, 1938 E. GUILLON ET AL SPARK PLUG Filed NOV. 8, 1935 luvs/v70?Emile GuiZZon and Jsc lnt Permult BY.QJM

AT TOR/YE) Patented Feb. 15, 1938 UNITED STATES PATENT OFFICE SPARK PLUGApplication November 8, 1935, Serial No. 48,915

4 Claims.

This invention relates to improvements in a spark plug and appertainsparticularly to one of advanced design as regards the central electrodeand reinforced surrounding supporting structure.

An object of the invention is to provide a spark plug having a sparkintensifying gap provided as by forming the central electrode in twoparts with an intervening space.

A further object of the invention is to provide an improved spark plugdesigned to reinforce the outer or exposed end thereof.

A further object of the invention is to provide a spark plug wherein theouter end of the porcelain is surrounded by a perforated guard closed 5at the top by an insulating cap to centre and steady the projectingelectrode.

A still further object of the invention is to provide a spark plug ofthe nature and for the purposes described, that is characterized bystructural simplicity, durability, efficiency and relatively low cost ofproduction, whereby the same is rendered commercially desirable.

To the accomplishment of these and related objects as shall becomeapparent as the descrip tion proceeds, the invention resides in theconstruction, combination and arrangement of parts as shall behereinafter more fully described, illustrated in the accompanyingdrawing and pointed out in the claims hereunto appended.

The invention will be best understood and can be more clearly describedwhen reference is had to the drawing forming a part of this disclosurewherein like characters indicate like parts throughout the severalviews.

In the drawing the figure represents a ver tical cross section of apreferred embodiment of our improved spark plug.

In adapting the principle of our intensifying gap to a spark plug wehave found it necessary to provide a central electrode of radically newdesign and secondly, in view of the support the porcelain loses by thisbreaking of the central electrode, a completely redesigned outer end forthe plug. With reference to the latter change,

' it may be here pointed out that while of major importance to thesuccess of the plug, it involves only minor structural variations, i.e., the upward extension of the locking ring to the height of theporcelain in the form of a surrounding cylinder and the closing of thetop thereof with an insulating and electrode centering cap.

In this improved spark plug, a porcelain stem 1 of substantially usualdesign and a usual plug base 2 are employed. The central electrode isformed in two parts however 3 and 4, the former being the lower end thatextends about or of. the way up the porcelain and is firmly securedtherein by a relatively wide thin annular flange 5 that is embedded inthe porcelain l where its major diameter occurs in the seat of the plugbase 2; while the upper end 4 has a similar though somewhat smallerflange 6 dividing its bottom portion, of the same diameter as the lowerelectrode and spaced therefrom by an air gap from the top portion 1,substantially thicker and threaded, that rises above the porcelain inthe usual way. It will be observed that the gap is placed towards thetop where the porcelain is thinner and can be easily kept cool andfurther since less of the upper electrode part 4 is embedded in theporcelain it relies for anchorage on both the flange 6 and threaded partI of which latter as much as possible, is provided. An ordinary toppingnut 8 threads on the electrode top 1 down against the porcelain.

The locking ring 9 that threads to the plug base 2 to hold the porcelainl is now made to include an integral cylinder part ID that rises to theheight of the porcelain, or the topping nut 9 Where one is provided.Rows of perforations ll occur in the lower portion of this cylinder, toabout the height of the gap in the central electrode, to cool andventilate the porcelain. The open upper end of the cylinder I0 isinteriorly threaded as at !2 to receive an insulating fibre cap l3centrally perforated at H to accommodate the exposed upper end I of theelectrode part 4 over which the usual terminal receiving or clamping nutI5 threads on the electrode end.

From the foregoing description taken in concontained in the saidaccompanying specification and drawing, shall be interpreted asillustrative and not in a limitative or restrictive sense.

Having thus described the invention, what is claimed as new is:-

1. In a sparkplug having a usual base and porcelain, a two-piece centralelectrode in said porcelain and a gap between the two parts thereof, thelower piece of said electrode having a wide thin flange embedded in theporcelain at its major diameter Where it seats in the plug base, and theupper piece having a similar though somewhat smaller flange near itslower end and a substantially thickened and completely threaded partrising upwards from said flange to a point beyond the porcelain top.

2. In a spark plug including a porcelain, a plug base, a locking ring, aperforated cylindrical guard for said porcelain integral with the saidring, and an insulating cap threaded in the top of said cylindricalguard and bearing down on said porcelain.

3. In a spark plug, a locking ring having an integral cylinder risingtherefrom, rows of perforations therein, one of said rows beingsubstantially level with the bottom thereof, and interiorly threaded atits upper end.

4. In a spark plug, a porcelain, a plug base, a two piece centralelectrode in said porcelain whose parts are separated by a gap about 80%of the way to the top, a locking ring threading to said plug base, anintegral cylinder rising therefrom, ventilating ports therein, interiorthreading in the top of said cylinder and an insulating fibre capthreaded into the top of. said cylinder to bear down on said porcelainand having a central opening to accommodate the projecting upper end ofsaid electrode.

EMILE GUILLON. JOSEPHAT PERRAULT.

